Vehicle transmission systems, cooling systems, and braking systems may employ clutches or like devices to selectively transmit rotational forces from a drive source to an output member. For example, some cooling systems employ fan clutch systems that control the output rotation of engine cooling fans. A fan clutch may be driven by a drive pulley that rotates in response to the vehicle engine.
In general, a clutch may be operated to engage (or disengage) opposing clutch surfaces, which rotationally interconnect (or rotationally disconnect) a drive pulley and an output member. In an example related to fan clutches, when clutch surfaces are shifted to the engaged position, an output member (carrying fan blades) may be driven to rotate along with a drive pulley. However, when the clutch surfaces are shifted to the disengaged position, the output member is no longer directly urged by the drive pulley.